There have been some site issues, but not a continuing one for 2 weeks preventing the ability to list for that period.
You have nearly a thousand items listed, perhaps you have hit your selling limit?
See here you actual allowance and there's a link there to ask for an increase if necessary.
If it is not granted you are asking a little too soon.
http://pages.ebay.co.uk/help/sell/sellinglimits.html
If the selling allowance is not the issue here, and you are still prevented from listing contact eBay Customer Services, they have full access to your account and can see where the problem lies.
Contact them this way.
https://www.ebay.co.uk/help/contact_us?id=4814&st=10
The contact links can be found on the left on that page.
Lines open on a weekend between 9 a.m. and 6 p.m.
